Introduction/Background We aimed to study the impact of the adjuvant treatment of high grade serous ovarian cancer (HGSOC) on location and time of recurrence.

Methodology We retrospectively investigated data of 208 ovarian cancer patients that were treated in tertiary care unit in Toronto, Canada between 2010 and 2020. We included all stage III-IV HGSOC patients who were treated with primary debulking surgery (PDS) with at minimum optimal (<1cm) cytoreduction followed by paclitaxel and platinum based chemotherapy. Our primary goal was to study the factors leading to site of recurrence as defined by extra peritoneal, intraperitoneal and lymph node recurrence. Our secondary goal was to see is there a difference in timing of recurrence based on whether patients received IV (intravenous) or IP (intraperitoneal) chemotherapy. We used Cox regression analyses for progression free survival calculations.

Results In our cohort 208 patient, 152 received IP and 56 IV administration of adjuvant chemotherapy. The significant predictor of an extra peritoneal recurrences was the presence of extra peritoneal disease at time of diagnosis [HR 3.69 (1.72, 7.95), p<0.001]. The significant factors predicting In our cohort 208 patient, 152 received IP and 56 IV administration of adjuvant chemotherapy. The significant predictor of an extra peritoneal recurrences was the presence of extra peritoneal disease at time of diagnosis (HR 3.84, 95%CI (1.77, 8.30), p<0.001). The only predictor of intraperitoneal recurrence was whether patients received IP over IV chemotherapy (HR 0.30 (0.16, 0.59), p<0.001). Patients who were treated with IP chemotherapy had a longer PFS (HR 0.67, (0.46- 0.96), p=0.03) and OS (HR 0.60, 95%CI (0.37, 0.99), p=0.05) compared to patients who received IV chemotherapy.

Conclusion In our study population, IP chemotherapy was the only predictor of intraperitoneal recurrence and was superior in comparison to IV chemotherapy in advanced HGSOC patients.

Disclosures No.